Valve stems, particularly those used in tubeless, pneumatic tires, are used to allow gases, typically air, to be added or removed from a tire or pressure vessel. The valve stem is generally constructed with an air passage extending from the inner portion of a wheel or pressure vessel to the outer portion. A valve core within the air passage controls the flow of air through the valve stem and helps maintain the pressure within a tire or pressure vessel.
Valve stems, particularly those used on wheels, may become damaged or may degrade over time such that they lose pressure due to the failure of a valve core or the hardening and cracking of the rubber that provides a seal with the wheel or pressure vessel. As a result, periodic replacement of valve stems is necessary. Existing valve stems are designed to be installed into a wheel or pressure vessel by pulling the valve stem through a hole from the high pressure side to the low pressure side. In the case of a wheel, the valve stem is pulled from the tire side to the exposed portion of a wheel. This type of installation requires the removal of the tire, which may or may not need replacement at the time of a valve stem replacement.
Tire removal generally involves high levels of deformation of the tire to break the tire bead seal from the wheel. For some wheels, particularly two-part steel wheels that are found on many small off-road vehicles, such as golf carts and all-terrain vehicles, breaking the bead of the tire from the wheel will cause separation of the wheel parts. These parts, which may have rusted along their joining seam, may be difficult or impossible to re-align or re-seal and may necessitate wheel replacement. Even in the case of single-piece wheels, the replacement of a valve stem requires removal of the tire, leading to possible damage from breaking the bead seal, and additional labor costs to re-mount and re-balance the tire for the replacement of the valve stem.
In certain cases, it may be desirable to provide a valve stem that can be installed from the exterior or exposed portion of a wheel or pressure vessel. A valve stem that may be installed from the unpressurized portion of a wheel or other pressure vessel may eliminate the need to open a pressure vessel or dismount a tire from a rim. In the particular case of pneumatic tires, eliminating the dismount, re-mount, and re-balancing of a tire may reduce the risk of tire damage or unseating of parts that may be difficult or impossible to re-seat or re-seal. A valve stem that may be installed from the unpressurized side of a wheel or pressure vessel may make valve stem replacement easier and reduce the amount of labor required for a routine repair.